Upgrade to Qiskit Nature 0.6.0

[mrossinek]

Summary

This upgrades the code to Qiskit Nature 0.6

Details and comments

Closes #22

[mrossinek]

I am not quite sure what to do with this in terms of release note. I am not changing any real code here so I think a release is not really necessary either :thinking:

[coveralls]

Pull Request Test Coverage Report for Build 4701489802

• 0 of 0 changed or added relevant lines in 0 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 69.697%

---

Totals
Change from base Build 4620793047:	0.0%
Covered Lines:	69
Relevant Lines:	99

---

💛 - Coveralls